Interferon, interferon inducers, and a variety of other immunomodulators are known to depress the hepatic cytochrome P-450 drug-metabolizing system. Two concepts have been proposed to explain this phenomenon. (a) The steady-state of cytochrome P-450 is altered through decreased synthesis and increased degradation of cytochrome P-450 apoprotein. (b) Interferon induces xanthine oxidase; superoxide generated by interferon-induced xanthine oxidase destroys cytochrome P-450. The current study investigated the second concept. Administered polyribonucleotides [polyriboinosinic acid.polyribocytidylic acid (poly IC), polyriboinosinic acid.polycytidylic acid, polylysine and carboxymethylcellulose, mismatched poly IC], recombinant murine gamma-interferon, and a natural murine alpha/beta-interferon were shown to depress hepatic cytochrome P-450 and selected microsomal cytochrome P-450-dependent monooxygenase reactions and to induce hepatic xanthine oxidase activity. The feeding of tungstate in the drinking water largely depleted xanthine oxidase in mice; cytochrome P-450 levels and monooxygenase activities were not affected by tungstate treatment. Tungstate rendered the level of xanthine oxidase much below that in mice that had not received tungstate regardless of whether or not they had received poly IC or interferon; nevertheless, poly IC and interferon produced losses of cytochrome P-450 and monooxygenase activities in these tungstate-treated mice equivalent to those observed in mice that had not received tungstate. The administration of N-acetylcysteine did not prevent the loss of cytochrome P-450 induced by poly IC, as has been reported, nor did the incubation of microsomal cytochrome P-450 with buttermilk xanthine oxidase and hypoxanthine cause a loss of cytochrome P-450, which has also been reported. It is concluded from these studies that the induction of xanthine oxidase and the loss of cytochrome P-450 generated by interferon are coincidental rather than causally related phenomena.
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Rat livers were perfused and stored for 48 hr in cold University of Wisconsin solution before dissociation by the two-step collagenase method. At that time, glycogen content was significantly reduced, but no obvious changes in albumin, beta-actin and aldolase B mRNAs and in glutathione levels were observed. Enzymatic perfusion yielded 280 +/- 30 x 10(6) viable hepatocytes vs. 520 +/- 40 x 10(6) viable hepatocytes from unstored organs. Cell viability determined by trypan blue exclusion was 74% and 90%, respectively. Hepatocytes from University of Wisconsin-preserved livers had a 29% reduced adenosine triphosphate content, but glutathione levels did not significantly differ from those found in unstored cells. When put into culture, hepatocytes formed typical monolayers of granular epithelial cells and did not exhibit alteration of their fine structure when compared with cells from unstored organs. After 24 and 48 hr, they showed variations in cytochrome P-450 content and ethoxyresorufin O-deethylase activity similar to those observed with unstored cells. By contrast, overall protein synthesis and albumin secretion rate were 40% and 30% lower, respectively. Hepatocytes from University of Wisconsin-preserved organs could be cryopreserved and further cultured as unstored cells. The University of Wisconsin solution was also used to preserve isolated hepatocytes. Viability of freshly isolated hepatocytes was decreased by only 10% after 48 hr of hypothermic liver storage when assayed by intracellular lactate dehydrogenase content. However, after 4 hr of storage, in contrast with hepatocytes preserved in L15 Leibovitz medium, the cells attached poorly to plastic and exhibited morphological alterations.(ABSTRACT TRUNCATED AT 250 WORDS)
Flow cytometry can be a valuable tool for parasitology in studies of parasite-drug interaction and cellular toxicity. This unit presents protocols for assessment of Leishmania promastigote proliferation, viability, and cellular protein content. The cytometric approach permits one to detect, differentiate, and quantify cellular changes in these parasites resulting from drug treatment, in this case allopurinol, as well as demonstrate differences in drug susceptibility between promastigote forms. Rapid and relatively simple flow cytometry replaces incorporation of [3H]-thymidine, hitherto the most common method for determining cell division.
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We have previously reported that human hepatic sinusoidal mononuclear cells may have a higher sensitivity to induction of apoptosis than peripheral blood mononuclear cells. In this study, the effects of two different preservation solutions on the functions of those hepatic mononuclear cells were evaluated in living-related liver transplantation.
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Acquired perforating dermatosis is a rare perforating skin disorder characterized by intensely pruritic papules or nodules with central adherent plugs mainly observed on the lower extremities and transepidermal elimination of collagen bundles. Treatment of acquired perforating dermatosis is a matter of debate and conventional treatment options including topical and systemic retinoids, topical corticosteroids and keratolytics, ultraviolet B phototherapy, psoralen plus ultraviolet A (PUVA), allopurinol and cryosurgery show mixed results. Herein, we describe a 60-year-old woman with a diagnosis of acquired perforating dermatosis secondary to diabetes mellitus in whom we achieved excellent results with photodynamic treatment. As far as we are aware, this is the first case report of photodynamic treatment for acquired perforating dermatosis.
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Rat liver was stored at 1 degree C in University of Wisconsin solution, and morphological changes were observed after 12, 18, 24, and 36 hr by transmission electron microscopy. There were two types of endothelial cell damage in the hepatic sinusoids. One was disruption of the endothelial linings, and the other detachment of endothelial cells into the sinusoidal space accompanied by fat-storing cell abnormalities. The former damage was seen after storage longer than 12 hr, while the latter developed after 18 hr even in the hepatic sinusoids with no disruption of the linings. Considering that fat-storing cell damage can produce endothelial cell destruction, this damage should be given attention as one of factors of endothelial cell destruction in the hepatic sinusoids after cold storage of the liver.
American Cancer Institute rats (n = 48) were divided into 6 groups. Hearts were arrested by coronary perfusion with 3 ml 4 degrees C University of Wisconsin solution at 60 mmHg. Eighteen donor hearts were divided into 3 groups of 6 and arrested either 1 hour after intraperitoneal injection of 3 ml oil with (Prob Tx) or without (Oil Tx) probucol (300 mg/kg) or without injection (Ctrl Tx). After a 90 minute storage period, abdominal isografting was performed with a total ischemic time of 2 hours. Following 15 minutes of blood reperfusion, donor hearts were rearrested and excised. Recipients' native hearts (NH, n = 18) were also arrested. Two additional groups with (Prob NR, n = 6) and without (Ctrl NR, n = 6) probucol pretreatment were arrested and subjected to 2 hours of ischemia without reperfusion. Postmortem LV pressure-volume curves and myocardial water content (MWC) were measured.
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Selective medical therapy significantly decreased stone formation rates in the stone-free (0.67 stones per patient per year vs 0.02) and residual fragment groups (0.67 stones per patient per year vs 0.02) as determined by the Wilcoxon signed rank test (p<0.0001). Moreover, remission was observed in a higher proportion of patients in the medically treated stone-free and residual fragment groups (87% and 77%) when compared to the same groups without medical therapy (29% and 21%, chi-square test p<0.0001).
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Allopurinol (1,5-dihydro-4H-pyrazolo [3,4-d]pyrimidin-4-one), the active pharmaceutical ingredient (API) of the drugs applied for the treatment of gout and tumor lysis syndrome, recently discovered to have multifaceted therapeutic potential, and hypoxanthine which is a naturally occurring purine have been studied experimentally in the solid state by (1)H-(14)N NMR-NQR double resonance. Twelve (14)N resonance frequencies have been detected at 295 K and assigned to two pairs of two kinds of nitrogen sites (-N═ and -NH) in each compound. The experimental results are supported by and interpreted with the help of quantum theory of atoms in molecules (QTAIM)/density functional theory (DFT) calculations. The factors, such as the substituent effect, in particular the shift of nitrogen from position 7 (as in hypoxanthine) to position 8 (as in allopurinol), hybridization, possible prototropic tautomerism, and the pattern of intermolecular bonding, have been taken into account in (1)H-(14)N NMR-NQR spectra interpretation. This study demonstrates the advantages of combining NQR, DFT/QTAIM, and Hirshfeld surface analysis to extract detailed information on electron density distribution and complex H-bonding networks in crystals of purinic type heterocycles, relevant in pharmacological processes. In the absence of X-ray data for xanthine, the NQR parameters supported by DFT/QTAIM calculations and Hirshfeld surface analysis were proved to be valuable tools for clarifying the details of crystalline packing and predicting an unsolved crystalline structure of xanthine. The influence of a decrease in purine ring conjugation level upon oxidation on the biological activity of allopurinol, a xanthine oxidase (XO) enzyme inhibitor, which blocks the conversion of hypoxanthine to xanthine and subsequently xanthine to uric acid, is also discussed.
Skeletal muscle edema secondary to an increase in capillary permeability after reflow is an important cause of the compartment syndrome after acute arterial revascularization. The purpose of this study was to investigate the possible role of oxygen free radicals, generated at reperfusion, in the pathogenesis of the compartment syndrome secondary to acute arterial ischemia/reperfusion. A reproducible model of this syndrome was produced in anesthetized rabbits by femoral artery occlusion after surgical devascularization of collateral branches from the aorta to the popliteal artery. Increasing periods of ischemia from 6 to 12 hours, followed by 2 hours of reperfusion, were associated with corresponding increases in the anterior muscle compartment hydrostatic pressure and inversely proportional decreases in tibialis anterior muscle blood flow within that compartment as assessed by xenon 133 washout (n = 46) (r = -0.62, p less than 0.001). Anterior compartment pressure increased from 5 +/- 1 to 48 +/- 5 mm Hg (n = 46) (p less than 0.001) after 7 hours of total arterial ischemia and 2 hours of reperfusion. Ablation of free radicals generated from xanthine oxidase with either allopurinol (n = 8) or oxypurinol (n = 8), by scavenging the superoxide radical at reperfusion with superoxide dismutase (n = 8), or by blocking secondary hydroxyl radical formation with deferoxamine (n = 8) significantly ameliorated the rise in compartment pressure (p less than 0.05) in each case; it also significantly improved muscle perfusion in the superoxide dismutase-, allopurinol-, and deferoxamine-treated animals (p less than 0.05). These findings indicate that development of the compartment syndrome after acute arterial revascularization may be due, at least in part, to microvascular injury mediated by oxygen-derived free radicals generated from xanthine oxidase at reperfusion.
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Rats were anesthetized and their lift kidneys were made ischemic for 1 h by clamping of the aorta just above the left renal artery. Mannitol (2.5 g/kg), Dextran 70 (0.6 g/kg), methylprednisolone (50 and 100 mg/kg), and allopurinol (100 mg/kg body weight) were administered before, during, or after the ischemia period in order to test the effect of each of these drugs upon this model of renal injury. At 24 h after the release of the aortic clamp the left kidneys of the drug treated animals wwere perfusion fixed and processed for light and electron microscopy. Dextran administration to animals with ischemic kidneys gave rise to a pronounced vacuolization ("osmotic nephrosis"), in the entire proximal tubule and especially in the pars recta. This was in contrast to dextran administration to rats with nonischemic kidenys, which showed no or very mild "osmotic nephrosis." This demonstrates that ischemia makes rat kidneys more susceptible to the development of "osmotic nephrosis." In controls (no drug treatment) one hour of renal ischemia gave partial necrosis of pars recta of the proximal tubule, while the pars convoluta tubule survived. Mannitol treatment significantly reduced the amount of necrosis of the pars recta, whereas dextran, methylprednisolone, and allopurinol had no or a negative effect on the survival of the cells of the pars recta segment. It is suggested that mannitol protects against the development of necrosis by increasing medullary blood flow in combination with a counteractive influence on the cellular swelling, which is known to occur in ischemia.
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Common drugs associated with DIHS include (but are not limited to) antiepileptics such as carbamazepine, phenytoin, and valproic acid; antituberculous drugs; sulfasalazine; allopurinol; and antivirals such as abacavir and nevirapine. Relapses may occur even after cessation of the culprit drug and appropriate management with corticosteroids. Studies have suggested that reactivation of herpesvirus, particularly, human herpesvirus 6, is the main cause of relapses. However, other pathomechanisms have been proposed - case reports have described the importance of drug cosensitization. In such cases, the introduction of a second drug (often an antibiotic) induces the relapse of DIHS. DIHS may also cause multiple drug allergies, where a patient develops sensitisation to other drugs which were previously well tolerated.
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To assess the effects of ulcerogenic agents on actin cytoskeleton and cell motility and the contribution of oxidative stress.
One hundred and seventy patients were enrolled and randomized to two groups: a study group (n = 85) who received 300 mg of oral allopurinol at 15 h and 3 h before endoscopic retrograde cholangiopancreatography (ERCP) and a control group (n = 85) receiving an oral placebo at the same times. Main Outcome Measurements included serum amylase levels and the number severity of the episodes of pancreatitis. Serum amylase levels were classified as normal (< 150 IU/L) or hyperamylasemia (> 151 IU/L). Episodes of PEP were classified following Ranson's criteria and CT severity index.
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Data were collected from 124 patients with newly diagnosed acute lymphoblastic leukemia (ALL) and WBC greater than 200,000/microL seen at institutions affiliated with the Children's Cancer Study Group (CCSG) from April 1981 to May 1983. The presenting characteristics, initial management, early complications, and outcome were reviewed. All the children received vigorous intravenous (IV) hydration, alkalinization of the urine, and allopurinol. Thirty-two patients were started on full therapy with no additional measure. One or more special measures believed to reduce the complications of leukostasis and blast cell lysis were administered to 92 patients as follows: small initial doses of prednisone, 63; emergency cranial irradiation, 26; exchange transfusion, 21; and leukopheresis, 19. The incidence of CNS hemorrhage was only 3% (4/124). Seven patients expired during induction and four failed to achieve a remission by day 28. Nineteen patients (15%) had documented bacterial or fungal sepsis. Mild to moderate electrolyte abnormalities occurred in 29 patients: three patients required renal dialysis. Pretreatment with small doses of prednisone did not decrease the incidence of electrolyte abnormalities in those patients when compared with patients who received full chemotherapy. The event-free survival (EFS) for the 106 patients treated on one of the three intensive pilot studies is 55% at 36 months. On multivariate analysis the two significant adverse prognostic factors were massive splenomegaly (P = .02) and WBC count greater than 600,000/microL (P = .05). In conclusion, in patients with hyperleukocytosis the complications of blast cell lysis and leukostasis were manageable with acceptable morbidity and minimal mortality in a group of patients treated with vigorous hydration, allopurinol, and alkalinization of the urine before beginning chemotherapy. Selected patients with severe hyperuricemia and renal dysfunction may benefit from leukopheresis. No beneficial role was demonstrated for the use of small initial doses of prednisone or emergency cranial irradiation.
Searches of MEDLINE (1966-October 2006), the Cochrane Library, and International Pharmaceutical Abstracts (1970-October 2006) were conducted using the terms allopurinol and schizophrenia. Limits were set to select studies conducted in humans.
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When adverse reactions occur, it is important to identify the etiologic drug. We describe a case of hepatitis associated with allopurinol. A 66-year-old female was admitted for rehabilitation of a cerebral hemorrhage on September 11, 1981. Allopurinol, clofibrate, and baclofen were administered. Severe hepatitis developed on November 13. The clinical laboratory data returned to normal on November 30. Challenge tests were conducted on clofibrate, allopurinol, and baclofen. The challenge test was positive after the administration of allopurinol. Allopurinol hepatitis is most likely a hypersensitivity reaction, as is suggested by the symptoms of eosinophilia and rash. Renal dysfunction may predispose one to develop hepatitis associated with allopurinol.
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Gout is common in the elderly and its management is frequently complicated by the presence of co-morbid conditions and medications prescribed for other conditions. The management of gout is 2-fold: (i) treatment of the acute attack to rapidly resolve the pain and inflammation; and (ii) long-term urate-lowering therapy (ULT) to prevent further gouty episodes. NSAIDs, colchicine, corticosteroids and more recently interleukin (IL)-1 inhibitors are effective treatments for acute gout. The choice of agent is determined by the patient's age, co-morbidities and concomitant medications. Renal impairment is of particular concern in the elderly and may preclude the use of NSAIDs and colchicine. The IL-1 inhibitors are rapidly effective but data in the elderly are limited. ULT aiming for a serum urate <0.36 mmol/L, or lower in severe tophaceous gout, is critical for the long-term management of gout. Urate lowering can be achieved by inhibiting the production of uric acid through xanthine oxidase inhibition (allopurinol, febuxostat), increasing uric acid excretion via the kidneys (uricosuric agents: probenecid, benzbromarone) or dissolving uric acid to the more water soluble allantoin (recombinant uricases: pegloticase, rasburicase). Allopurinol is the most commonly used ULT, but there is no consensus on dosing in renal impairment. Febuxostat is effective at lowering serum urate, but there are limited data in the elderly and patients with renal impairment. Furthermore, there are concerns about cardiovascular safety. Probenecid is ineffective in patients with renal impairment (creatinine clearance <60 mL/min) and the availability of benzbromarone is limited because of concerns about its hepatotoxicity. The recombinant uricases provide an exciting new therapeutic option, but there are limited data for their use in the elderly. These agents may be particularly useful in patients with a high urate burden (e.g. those with tophi); however, they may precipitate a severe flare of gout and this will require treatment in its own right. Careful consideration of the patient's concomitant medications is required as many drugs increase serum urate. Successful urate lowering will ultimately reduce gout flares and thereby improve patient quality of life.
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A 34-year-old woman was diagnosed with Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), most likelyrelated to a reaction to allopurinol.The patient presented with a 2-week history of a painful pruritic rash that started on her back and progressed to the rest of her body over a five-day period. The eruption started after several new drugs were started, including allopurinol for hyperuricemia. On physical examination, the patient had a diffuse morbilliform eruption and geometric intact bullae limited to the boundaries of tattoos.Most presentations of DRESS include a morbilliform eruption. However, DRESS does not commonly present with bullae. There have been no known reported cases of bullae forming in the area of tattoos in cases of DRESS. This unique presentation suggests that a component of the tattoo or tattooing process alters the cutaneous immune response, creating an immunocompromiseddistrict. This alteration may promote a greater localized reaction in the setting of widespread skin involvement in DRESS.
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To analyse production of free radicals during operations for stenosis of the internal carotid artery.
Livers were washed out with cool physiologic saline or with UW solution and subjected to rewarming ischemia for periods of 20 min or 45 min followed by reperfusion using a blood-free perfusion model.
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A 12-year-old girl, who had been diagnosed as having Cockayne syndrome (CS), was admitted for emaciation and dehydration. On admission the patient had mild chronic renal failure (glomerular filtration rate: GFR 50 mL/min) and hyperuricemia. After rehydration, allopurinol was commenced for her hyperuricemia. Then, her renal function rapidly deteriorated (GFR 20 mL/min) with enhancement of proximal tubular dysfunction and hypertension. A renal biopsy showed that the patient had acute tubulointerstitial nephritis (ATIN). Based on this diagnosis, allopurinol was stopped and prednisolone was started (2 mg/kg per day), following which the renal tubular function improved. However, the proteinuria intensified to become nephrotic syndrome. After 1 month the patient developed a gastric ulcer. Famotidine was commenced but GFR deteriorated and renal proximal tubular dysfunction re-occurred. The renal pathology was evaluated by referring to the previous reports of renal pathology in CS. It is suggested that rapid deterioration of the renal function in CS patients might be the result of ATIN. In addition, the present nephrotic syndrome seemed to be accompanied by ATIN, as in other reports.
Improvement of long-term heart preservation methods would potentially increase the donor pool and improve survival. We compared the efficacies of the University of Wisconsin (UW) and Celsior solutions on ventricular and endothelial functions after 24-h preservation.
Positive HLA-B*5801 carriers are at greater risk of experiencing rare but severe allopurinol hypersensitivity syndrome (AHS) [i.e., Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN)]; however, HLA-B*5801 prevalence and AHS risk vary by race/ethnicity. We evaluated the cost-effectiveness of HLA-B*5801 testing according to race/ethnicity in the United States.
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Thus rat LVPVCs can be improved after heart transplantation with alternative strategies of myocardial protection. KCl arrest decreases LV filling volume in this model and should be avoided.